Display screen or portion thereof with transitional graphical user interface



FIG. 1 is the first image in a sequence for a display screen or portion thereof with transitional graphical user interface showing our new design; and,

FIG. 2 is the second image thereof.

The outer perimeter shown in broken line in the drawings depicts a display screen or portion thereof and forms no part of the claimed design. The broken-lines that are congruent with the perimeters of white shapes shown in FIG. 2 show interior boundaries of the claimed design and form no part thereof. The remaining broken lines illustrate portions of the transitional graphical user interface that form no part of the claimed design.

The appearance of the transitional image sequentially transitions between the images shown in FIGS. 1-2. The process or period in which one image transitions to another image forms no part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with graphical user interface, as shown and described. 